The field of this invention is dead man safety assemblies, particularly of the type used for remotely operating a control mechanism.
In the interest of safety, typically a control valve can be of a "dead man" type, wherein the manually operative mechanism in the remote control valve is biased in a manner such that in order to be operable, the operator must maintain the mechanism in a certain position. Upon the release of the mechanism, it typically is designed to return to its "off" position. United States Pat. No. 3,543,444 and British Pat. No. 1,394,483 disclose electrically operative control valves while U.S. Pat. Nos. 3,834,082; 3,557,498; and 3,201,901 disclose fluid-actuated control valves. Other types of remote control valves include those having internal valving adjacent the control thereof as shown in U.S. Pat. Nos. 3,618,263 and 2,641,087. In U.S. Pat. No. 2,641,087, a pinch-type control valve adjacent a blast hose nozzle is utilized for controlling fluid flow therethrough and having a trigger-actuated release for opening such a remote control valve.
While a number of these references disclose handles or protective coverings which purportedly are to help prevent inadvertent actuation of the control valve, as shown in U.S. Pat. Nos. 3,834,082; 3,557,498; 3,543,444, or are of a bleeder-type valve construction as manufactured by the Sanstrom Corporation or by Clemco-Clementine, Ltd. under the "Recova-Lok" trademark or as in U.S. Pat. No. 3,201,901, so far as known, none provides a positive safety locking member that must be intentionally moved by the operator prior to making such a control valve operable. Further, as far as is known, none of the prior art discloses structure that automatically deactivates the control valve as well as requires positive, user-actuation of a safety mechanism prior to reuse of the remote control valve after such a control valve is initially released.